1. Field of the Invention
The present invention refers to the domain of machines connected to a telecommunication networks, in particular the management of virtual machines.
2. Description of the Related Art
The term virtual is very popular and generally refers to the modelling and simulation of a real system.
In the domain of computer machines, a classic example is the virtualization of a storage system.
In virtualization, instead of direct access to a hard disk, a machine accesses a virtual disk for which, the machine does not know the physical specifications. The storage requests are processed by a suitable interface that receives the storage or recovery demands and carries out the conversion to the physical disk(s). Furthermore, the hardware stock can be heterogeneous, for example, units of different types (magnetic disk, Flash memory etc) but the virtual representation is unique for a final user.
The principle is simple. When the storage capacity on this virtual unit exceeds the physical capacity, new physical units are added in a transparent way for the user.
Companies such as VMWare®, IBM® or Connectix® propose solutions that include software solutions towards a further step to virtualization, namely the creation of a complete virtual machine comprising the operational system part.
This solution allows sharing of a physical machine by creating several virtual machines, each virtual machine complying with suitable criteria in terms of storage means, calculation means and communication means.
The applications running on this type of virtual machine have the advantage of being easily transportable because they are independent of a physical machine. The virtual machine can be developed with the advancement of technology without requiring modifications to the applications.
As explained above, if more important requirements are highlighted for a given application, the physical machine is replaced and then the application is reactivated without any modification. The new display interface, network, etc., are processed in a specific way on the local layer of the virtual machine and a unique virtual image is defined for the application by the virtual machine.
This configuration simplifies the maintenance and the testing of new applications. In fact, the applications can operate transparently on several software environments running on the same virtual machine.
However, this configuration has limits since it is only applied on one machine. In the network configuration, a server is initialized by this virtual machine and several computers can operate different applications that can each be attached to a suitable operating system (Linux, Windows® 95/98, Windows® NT, etc.).
This virtuality presents limits because it takes into account that one machine and only one application level is possible.